Semi-automatic color change system for paint spray installation



R. F. WIGGINS 3,348,774 SEMI-AUTOMATIC COLOR CHANGE SYSTEM FOR PAINTOct. 24, 1967 SPRAY INSTALLATION 7 Filed March 18, 1965 4 Sheets-Sheet 1INVENTOR.

RICHARD E WIGGINS mm; 73 m mm -TIH YHHHHPHH HI 1 llll J ATTORNEYS Oct.24, 1967 R. F. WIGGINS 3,348,774

SEMI-AUTOMATIC COLOR CHANGE SYSTEM FOR PAINT SPRAY INSTALLATION FiledMarch 18,v 1965 4 Sheets-Sheet 2 1 w 58 so 59 1 6| '6 34 27 28 I I l M qI r I W 'lmmj' WW INVENTOR.

I RLCHARD F WIGGINS ATTORNEYS Oct.24, 1967 R. F. WIGGINS 3,348,774

SEMI-AUTOMATIC COLOR CHANGE SYSTEM FOR PAINT SPRAY INSTALLATION FiledMarch 18. 1965 4 Sheets-Sheet 5 FIG. 4

INVENTOR RICHARD E WIGGINS ATTORNEYS United States Patent ()fiice3,348,774 Patented Oct. 24, 1967 3,348,774 SEMI-AUTOMATIC COLOR CHANGESYSTEM FOR PAINT SPRAY INSTALLATION Richard F. Wiggins, Fairlield,Conn., assignor to The Gyromat Corporation, Stratford, Conn., acorporation of Connecticut Filed Mar. 18, 1965, Ser. No. 440,736 4Claims. (Cl. 239-70) ABSTRACT OF THE DISCLOSURE A valve controlled,semi-automatic color change system for industrial paint sprayinstallations having an independent, valve controlled, purge fluiddischarge line running from the paint spray head to a reclaim vessel.The system includes a plurality of valves connected in series forsupplying different paints and purge fluids to the paint spray head. Thepurge fluid supply valve is located upstream from the paint supplyvalves so that when the purge fluid is flowing through the system itcleanses the paint supply valves as well as the paint spray head andconnecting lines.

The present invention relates to industrial paint spray installations,and is directed more particularly to novel and improved semi-automaticarrangements for facilitating the changing from one paint color toanother with a minimum expenditure of time, paint loss, and area orspray booth contamination.

Industrial paint spray lines commonly are called upon to supply paint ina variety of colors in regular, day-to-day production. Theoretically, itwould be possible to provide a completely separate paint spray systemfor each color used in regular production, but this would be impracticalin most instances, because of the high cost of the initial installationand the undue complication of the controls and other facilities.Accordingly, it is customary to provide arrangements for purging andflushing out the paint spray system to remove all residue of afirst-used paint color, after which the system is filled with paint of asecond color and readied for further production. Particularly where thepaint spraying procedure is, carried out on a production line basis,with extensive conveyors and related facilities, it is important toeffect the changeover from one paint color to another very quickly on acontrolled and predictable basis so that there is a minimum of lostproduction. At the same time, it is desirable from an economy standpointto eliminate or minimize wastage of residual paints purged from thesystem during change-over, as well as of the purge fluids themselves.The present invention is directed to an improved and simplifiedapparatus which enables the foregoing objectives to be met in anautomatic and efiicient manner avoiding spray booth contamination withan installation of control facilities of essentially simplified nature.

In accordance with one aspect of the invention, an otherwise relativelyconventional paint spray installation is provided with a fluid supplysystem including a plurality of paint valves and a purge fluid valve,all connected in series, with the purge valve being upstream of thepaint valves. The paint spray nozzle or nozzles, supplied from the paintvalves, are, in addition, provided with discharge lines leading to acontrollable discharge valve. In conjunction with the before-mentionedcontrol valves, there are provided pressurized supplies of paints,purging solvent and purging air, and a novel, simplified sequencingcontrol system for effecting timed actuation of the various controlvalves and other control elements of the system on an automatic basis,whereby purging and recharging of the system is carried out quickly andwith utmost efliciency.

In addition to providing a novel and simplified overall system, theinvention is directed in part to the provision of control valves whichare novel and improved in themselves and which are utilized toparticular advantage in the overall system. According to the invention,control valves used for purge fluids, paints of various colors, and fordischarge may all be of substantially identical construction, arrangedto be secured in side-by-side relation. Each of the valves, except thedischarge or dump valve, has a flow housingl portion provided with athrough-flow passage, such that, when the individual flow housings aresecured together, a continuous common flow passage of smooth andrelatively uniform cross-section on the discharge side of the valves isprovided. Where necessary or desirable to isolate one flow housing fromanother, as in the case of isolating the discharge valve from the othervalves of the present system, a plug may be inserted at the end of aflow housing.

In accordance with the invention, an assemblage of individual controlvalves as described above presents a series flow passage of smooth andsubstantially uniform cross-section into which the individual controlvalves discharge. With respect to the downstream valves, at least, eachis provided with a controllable valve element which, when closed, formspart of the smooth and substantially uniform flow passage. In theassemblage, the valve positioned farthest upstream controls purgefluids, and these fluids travel downstream past the individual colorpaint valves, efficiently cleansing the system of unwanted paint of thepreviously used color.

In accordance with one specific aspect of the inven- F tion, anassemblage of valves of the type mentioned above may include a separate,individual control valve for each of a substantial plurality of paintcolors regularly utilized in production. As a simplified alternative forsmaller installations, the system may be arranged for the utilization ofonly two paint control valves, with a valve for a previously used paintcolor being completely purged and cleaned during change-over to a newcolor. During the next subsequent color change, the previously purgedvalve is connected to accept any desired new color of paint. An idealsystem according to the invention may advantageously comprise a givennumber of separate paint control valves which are connected at all timesto respective regularly used paint supplies, in conjunction with a pairof alternately usable control valves arranged for selective connectionto any of a large variety of less frequently used paint colors.

For a better understanding of the invention, reference should be made tothe following detailed description and to the accompanying drawing, inwhich:

FIG. 1 is a simplified, schematic representation of an industrial paintspray installation incorporating the color change system of theinvention;

FIG. 2 is a top plan view of a control valve assemblage incorporatingfeatures of the invention and suitable particularly for utilization inthe system of FIG. 1;

FIG. 3 is a front elevational view of the assemblage of FIG. 2;

FIG. 4 is an enlarged cross-sectional view taken generally on line 44-of FIG. 3;

FIG. 5 is a fragmentary plan view showing details of a paint spray headadapted for utilization in the system of FIG. 1;

FIG. 6 is an enlarged, fragmentary, cross-sectional view taken generallyon line 6-6 of FIG. 5; and

FIG. 7 is a time-function chart reflecting the sequence of events whichoccurs in a color change cycle.

Referring now to the drawing, and initially to FIG. 1, the referencenumerals 10, 11 designate paint spray nozzles of a typical industrialpaint spray installation. Advantageously, the paint spray head of whichthe nozzles 10, 11 form a part, are Gyromat ULPE electrostatic heads,made available by The Gyromat Corporation, Stratiord, Conn, although theinvention is not limited to paint spray heads of this specific design.

In a typical installation, there may be a number of spray headssimultaneously spraying the same paint color, and these would be fedwith paint from a manifold 12 supplying individual paint supply lines13. In the system of the invention, each of the spray guns 10, 11 alsohas a discharge, leading to a discharge line 14 and, where there are anumber of guns, into a discharge manifold 15. The discharge manifoldleads through a discharge line 16 through a normally closed,controllable discharge valve 17 to a discharge outlet 18. As willappear, the discharge outlet may be associated with a reclaim receptacle19 or a disposal receptacle 20, as may be expedient.

The supply header 12 is connected through a supply line 21 and apressure regulating valve 22 to the outlet port 23 of a controlvalveassemblage generally designated by the numeral 24, to be describedin greater detail herein. In general, the control valve assemblageincludes a housing assembly 25, providing an internal flow passage 26 ofsmooth and substantially uniform cross-section. The flow passage 26communicates at its upstream end with the outlet of a purge fluidcontrol valve 27 and at selected downstream points with individual paintcontrol valves 28, 29. For the purpose of the present illustration anddescription, only two individual paint control valves are illustrated,as all of the relevant principles of the invention may be incorporatedin a two-color system. However, it will be understood that moreextensive, high production systems may be assembled utilizing a greaternumber of individual paint control valves where desired. Each of thepaint control valves has its valve outlet communicating with the mainflow passage 26 of the housing assembly 25 for controllably directingpaint of a selected color into the system.

Where more than one spray gun is served .by the same delivery system, asin the illustration of FIG. 1, it is customary to provide each gun witha separate regulator R, which may be independently adjusted. In suchcases, all of the discharge lines 14 include individual check valves CV,so that all lower pressure lines will be isolated from the higherpressure lines when the discharge valve 17 is closed.

Each of the principal control valves 17 and 2729 of the illustratedsystem is pneumatically or electrically actuated and, for this purpose,includes an actuating bellows 30-33 connected by means of control lines34-37 and individual solenoid operated actuating valves 38-41 to an airsupply line 42. The supply line 42 is, in turn, connected through apressure regulator 43 to the main source 44 of compressed air. Bycontrolled, timed actuation of the actuating valves 3841 control isestablished over the opening and closing of the control valves 17,27-29, as will be understood.

Advantageously, and as will be described in more detail, each of theprimary control valves has two inlets controlled by the valve elementsand arranged to discharge fluid into the main flow passage 26 when theassociated primary control valve is open. Thus, the purge valve 27 hasits inlets connected to a purging air supply line 45 and a purgingsolvent supply line 46. The air supply line 45 is connected through acheck valve 47 and a soelnoid operated control valve 48 to the airsupply line 42. The arrangement is such that, when the control valve 48is open, air under pressure is supplied to the purge valve 27, fordischarge into the system upon opening of the purge valve. The solventsupply line 46 is connected through a check valve 49 and shut-off valve50 to a solvent supply container 51. The solvent supply is maintainedunder pressure by an air supply line 52 leading through a shut-off valveand a pressure regulator 53 back to the main air supply source 44. Forreasons which will become apparent, the output side of the pressureregulator 53 is significantly lower than the output side of theregulator 43, such that, in a typical installation, the air supply line42 is under about 60 pounds pressure (p.s.i.), while the solvent systemis maintained under about 40 pounds pressure.

The paint control valve 28, 29 have their inlets connected to individualpaint'supply lines 54, 55 through shut-off cocks 56, -57. Second inletsof the paint control valves are connected through shut-ofi cocks 58, 59with solvent supply lines 60, 61. In the illustrated system, in whichthe paint supply valves 28, 29 are intended to accommodate a largernumber of paint colors, the paint supply lines 54, 55 are provided withquick disconnect couplings 62, 63, by means of which the valves may bequickly connected with additional paint supply lines (not shown). Inaccordance with one aspect of the invention, the control lines 36, 37,which may be referred to for convenience as paint control and purgecontrol lines, respectively, are connected to selected paint controlvalves by means of quick disconnect couplings 64, 65. In this respect,it is contemplated that, regardless of the number of paint controlvalves utilized in the system, all would be serviced by a single paintcontrol line 36 and a single purge control line 37.

Control over the opening and closing of the spray heads 10, 11 iseifected by means of a master solenoid valve 66 which is energized froman independent, separately controlled source indicated by the B+ andground designations at the left in FIG. 1. Assuming that the B+ supplyhas not been switched out by the other control facilities (not shown),it can energize the solenoid of the master valve 66 through normallyopen contacts CR13a of a control relay CR13 and normally closed contactsof an energized control relay 67. The relay 67 is kept energized througha normally closed switch TSC when the system power is on throughswitches 68- and the equipment has not been energized to carry outacolor change cycle. When the master control valve 66 is in itsde-energized condition, air under pressure is supplied through lines 69to individual control conduits 70, 71 (see FIGS. 5 and 6) leading tothe. respective spray heads 10, 11.

As shown particularly in FIG. 6, each of the spray heads has anactuating bellows 72 which, when acted upon by the control air, advancesa plunger rod 73.to project a valve stem 74 through a predeterminedvalve opening stroke determined by the setting of an adjust ment nut 78.A return spring 76 acts upon a nut t0 reclose the valve when control airpressure is removed.

While specific details of the spray heads do not form a part of thepresent invention, the spray heads, for the purpose of incorporationinto the overall system of the invention, include paint supply chambers77 communicating with the paint supply lines 13 and discharge lines 14.Additionally, the spray heads are supplied with atomizing air facilities(not shown) in accordance with known practices.

With reference'now to FIGS. 2-4, there is shown a control valveassemblage according to the invention, which is particularly suited forincorporation in the system of FIG. 1. The illustrated assemblageincludes four control valves of substantially identical construction,the

individual features of which are illustrated in FIG. ,4. Thus, eachvalve includes a flow housing 80 provided with a longitudinal flowpassage 81 extending from one end to the other. At its end extremities,the flow housing is provided with outwardly extending flanges 82'adapted to be bolted or otherwise secured to the similar flanges ofadjacent valves or to mounting brackets 83. In the upper portion of,each of the flow housings 80,

there is a machined recess 84 which extends downward and into opencommunication with the longitudinal flow passage 81, which ishorizontally oriented in the illustrated arrangements. A valve housing85 having a downwardly projecting machined boss 86 is secured influid-tight relation to the flow housing 80, with the boss 86 beingreceived in and maintained in sealed relation with the recess 84. Thevalve housing 85 is provided at its lower end with a hardened and groundvalve seat 87 of annular form, the opening of which communicates with alower, primary valve passage 88 and an upper, secondary valve passage89.

An elongated hardened and ground valve stem 90 extends through the valvepassages 88, 89, being slidably guided in the secondary valve passage89. At its lower end, the valve stem has a conical valve head 91 whichcloses against the annular valve seat 87 in the manner shown, such thatthe lower surface 92 of the valve head forms part of the wall of theflow passage 81. The arrangement is such that the fiow passage 81, fromone end to the other of the flow housing 80, is smooth and relativelyuniform in cross-section, affording a relativley minimum opportunity toform eddies and collection pockets which would reduce the efliciency ofclean-out.

At its upper end, the valve stem 90 connects with a bellows element 93which is located within a bellows housing 94 and forms a seal betweenthe housing and the valve passage 89. The bellows is normally urgedupward by a spring 95, but is actuated in a downward direction byintroduction of pressure fluid (air) into the bellows chamber 96 througha quick disconnect control air fitting 97.

The specific valve illustrated in FIG. 4, which is the downstream paintvalve 29, has its flow passage plugged on the downstream side and isprovided with a fitting 98 in its bottom outlet port 23, which causesthe fluid flow to be discharged into the supply line 21. The valve isalso connected to the solvent line 61, through stop cock 59 and to thepaint supply line 55 (downstream of the quick disconnect fitting 63)through the stop cock 57. The paint supply discharges into the primaryvalve passage 88, while the solvent supply discharges into the secondaryvalve passage 89, upstream of the paint supply.

In accordance with the invention, a complete installation advantageouslyincorporates a unitized bank of primary control valves, including thedischarge valve 17 and purge valve 27, as well as paint valves 28, 29.Actually, the discharge valve 17 may be located elsewhere in theinstallation, without inconvenience, but it is particularly advantageousfor the purge valve and paint control valves to be arranged in aunitized bank, as shown in FIGS. 2 and 3. Thus, a series of primarycontrol valves including the purge valve and as many paint controlvalves as may be desired to be used in the system are assembled inend-to-end relation, with their respective flanges 82 in abuttingrelation and secured together in a fluid-tight manner by bolts or othersuitable means (not shown). The arrangement is such that the flowpassages 81 of the respective flow housings are aligned and incommunication' to form an elongated, relatively smooth passage ofrelatively uniform cross-section from one end to the other.

In a complete assembly of valves, a suitable plug 99 is inserted in theupstream end of the flow passage of the purge control valve 27, while asimilar plug 100 is inserted in the downstream end of the flow housingof the downstream paint valve 29. Other suitable plugs close off two ofthe three openings of the flow housing for the discharge valve 17, whilethe remaining opening, advantageously at the bottom, is connected withthe discharge line 18 through a fitting 101. The discharge valve is thusisolated from the other valves of the installation.

As shown in FIG. 3, suitable plugs 102 close oif the bottom outlets ofthe upstream control valves, while the discharge outlet 23 in the bottomof the downstream 6 control valve 29 is connected with the supply line21 through the fitting 98.

The entire bank of control valves, as shown in FIGS. 2 and 3, forms aconvenient unitary assembly, which is secured at each end-to suitablemounting brackets 83.

Operation of equipment The operation of the system is best describedwith reference to a description of the sequencing timer arrangementillustrated in FIG. 1 and to the time-function chart illustrated in FIG.7. Advantageously, the sequence timer is a conventional,electromechanical timer including a timing motor 103 arranged to operatethrough a timing cycle and actuate a plurality of timer switch contactsT1CT7C by means of a plurality of preset cams (not shown) which may beindividually adjusted with respect to the several switch contacts toachieve a desired timing sequence, in accordance with conventionaltechniques.

When the system is operating and in readiness for color change, thetiming power supply switch 68 will be closed and typically, although notnecessarily, the spray heads 10, 11 will be in operation. Under assumedinitial conditions, the actuating valve 39 is open and the paint controlvalve 28 previously has been actuated to an open condition supplying apaint to the system. The paint stop cock 56 is open and the solvent cock58 is closed so that a first color paint is being supplied through theline 54 and valve 28 and into the main flow passage 26 of the valveassemblage. The actuating valve 40 and therefore its associated paintcontrol valve 29 is de-energized and closed, as are the actuating andcontrol valves 38, 27 for controlling purge fluids. The stop cocks 57,59 associated with the paint control valve 29 are closed. The aircontrol valve 48 is deenergized and open, so that air under pressure issupplied to the closed purge valve 27, as is solvent under pressurethrough the unvalved line 46. The actuating valve 41 is de-energized andclosed, as is its associated discharge valve 17.

To commence a color change cycle, a start button S is depressedmomentarily to energize the timing motor 103. The start button is heldclosed until the motor advances slightly, enough to close holdingcontacts T1C which are connected in parallel with the start switch. In atypical second color change cycle, it is contem lated that the holdingcontacts TIC will close in about 3 seconds. They will thereafter remainclosed until reopened by the cam to stop the motor and terminate thetiming cycle.

Simultaneously with the closing of the holding contacts TIC, timercontacts T2C, T6C2 and T7C are closed and contacts TGCl are opened.

The closing of timer contacts T7C causes the energization of the controlrelay CR13 which closes contacts CRl3a in the B-lenergizing circuit ofthe master solenoid valve 66, such that the valve is energized andclosed to shut off the spray heads. The closed contacts T7C alsoenergize the actuating valve 41, admitting pressure fluid to the line 34to the bellows of the discharge valve 17, so that the discharge lines14-16 are placed in communication with the reclaim or disposalcontainers 19, 20, as the case may be. Typically, in order to conservepaint for reuse, the discharge lines are connected to the reclaimcontainer 19, at least during the initial stages of the color changecycle, when reusable paint is being purged from the system.

Opening of the timer contact T6C1 effects de-energization of theactuator valve 39, closing olf the air supply to the then-active paintcontrol valve 28 to close this valve and block off any further flow ofpaint to the system. The companion timer contact T6C2, when closed atthe start of the cycle, simultaneously energizes actuating valves 38, 40to admit pressure fluid through the lines 35 and 37 to open the purgefluid valve 27 and the inactive paint 'valve 29. With the stop cocks 57and 59 closed, however, opening of the inactive paint valve is withoutconsequence. Closure of contacts T6C2 also brings about the energizationof a 7 solenoid control 104 of the pressure regulator 22, which has theeffect of decreasing the pressure drop across the regulator, enablingthe purging and recharging of the system to take place with greaterrapidity. Typically, the outlet side of the regulator 22 will have anoperating pressure of about p.s.i., and this will be increased to about20 p.s.i. when the solenoid 104 is energized but returns to its originalsetting at the end of the color change cycle.

Along with the closure of timer contacts T6C2 and T7C, contacts T2C areclosed to actuate the air control valve 48 to an open condition. Thisimmediately admits purging air into the now-open purge control valve 27,and this air, at a typical pressure of about 60 p.s.i., advances throughthe flow passage of the valve assemblage, through the supply lines 21,13, and out through the discharge lines 14-16, through the dischargevalve and discharge line 18, forcing the main body of paint through thesystem ahead of it and expellingit into the reclaim container 19. Thisinitial air purge advantageously continues for a period of about 15seconds.

During the air purge interval, the operator of the system carries out asequence of manual operations comprising closure of the paint stop cock56, switching the controlled pressure fluid lines 36, 37, so that theactive control line 37 is connected to the just-used paint valve 28,while the inactive control line 36 is connected to the paint valve 29.Thereafter, the stop cocks 57 and 58 are opened to admit a second colorpaint up to the closed valve 29 and to admit solvent and purge air tothe just-used paint valve 28, which is now open by admission of pressurefluid through the line 37. This sequence of manual operations may becarried out quickly and conveniently by reason of the quick disconnectcouplings 64, 65 and the convenient grouping of the various stop cocks,so that the operations are completed well within the 15 second periodduring.

which air purging of the system is being carried out.

It will be understood that, during the initial air purge interval, anopen solvent line is connected to the purge valve 27 and, after openingof the stop cock 58, also to the just-used paint valve 28. Nevertheless,solvent does not at this time enter the system because the purging airis at a substantially higher pressure thanthe purging solvent in theline 46, causing the solvent to be held back by the air. Solvent is notbacked up in the line 46 by the higher air pressure however, because ofthe interposition of the check valve 49 in the solvent supply line.

At the end of the air purging interval, the timer contact T2C isreopened, de-energizing and closing the purging air control valve 48.The purge control valve 27 remains open, however, and the solvent, withthe restraining back pressure removed, advances through the purge valveand also through the just-used paint valve 28. The solvent travelsthrough the paint supply lines and the discharge lines in the samemanner as just described with respect to the purging air, cleansingresidual paint from the system. Advantageously, the discharge line 18 isredirected at this time into the disposal container 20, or perhaps intoa second reclaim container, so as not to contaminate the paintpreviously discharged into the reclaim container 19.

Advantageously, the solvent purge interval continues for about 40seconds and, at some time during this interval, the timer contact T5Copens for a brief period, say 10 seconds, to de-energize the controlrelay 67 and momentarily de-energize and open the master control valve66. This opens the spray heads 10, 11 for a brief interval, causingsolvent to be discharged therefrom to cleanse the nozzle areas ofresidual paint which cannot be removed during the normal flow of solventand air through the supply and discharge lines 13, 14. If desired,during this interval, the paint supply line 54 for the just-used colormay be disconnected at the fitting 62, and a new supply line carrying athird color may besubstituted therefor to supply new color paint up tothe closed stop cock 56.

After a predetermined solvent flush period, timer contacts T4C areclosed, and this re-energizes the purging air control valve 48, suchthat the flow of purging air is reestablished, and further solvent flowis stopped by reason of the higher back pressure of the purging air. Thesecond air purge interval is continued for a period of about 15 seconds,during which the solvent, with which the system is at that time charged,is purged forward out of the system and discharged into the disposalcontainer 20.

During this interval, the operator may close the solvent cock 58associated with the just-cleansed paint valve 28.

At the end of the second air purge interval, timer contacts T6C arereactivated'so that contacts T6C1 are reclosed and contacts T602 arereopened. Actuating valve 39 is thereupon energized and opened,actuating the paint valve 29 to an open condition and causing paint of asecond color to be discharged into the system. The actuating valve 40 isat the same time de-energized and closed, to deactivate and close thepreviously used paint valve 28. Simultaneously, the regulator solenoid104 is de-energized so that the output of the regulator isre-established at the normal, low pressure desired.

In order to fully charge the system with paint of the new color, aninterval is provided during which the new color paint valve 29 isopenand discharging paint into the system and the discharge valve 17 is openand discharging air.

The nozzle regions of the spray heads 10, 11 are, at this stage, filledwith solvent, and itis desirable to reopen the spray head valvesmomentarily during the charging of the system with new paint, so thatthe residual solvent is discharged and the nozzles are primed with thenew paint. This is brought about by reclosure of the timer contacts TSCduring the paint charging interval.

After a paint charging interval of about 18 seconds, the timer contactT1C is opened, along with timer contacts T7C. This de-energizes themotor 103 to end the color change cycle and simultaneously de-energizesthe actuating valve 41 to close the discharge valve 17 and energizes thecontrol relay CR13 to reactivate the spray heads 10, 11.

Advantageously, a series of indicator lights 105-108 is provided inconnection with the sequence timer, to keep the operator apprized of theprogress of the color change cycle. Thus, the indicator light 105 isarranged to be energized upon closure of the main switch 68, to indicatea ready condition. The indicator light 106 is energized by closure ofeither contacts T2C or T4C and indicates the carrying out of the airpurge intervals, before and after the intervening solvent cleansinginterval. An indicator light 107 is energized by timer contacts T3C,arranged to be closed simultaneously with the opening of the contactsT2C and to be opened simultaneously with the closure of contacts T4C.Thus, energization of the signal light 107 reflects the carrying out ofthe solvent cleansing interval. The signal lamp 108 is energized byclosure of timer contacts T6C1 and reflects the actuated condition ofwhichever one of the paint control valves 28 or 29 is connected tothepressure fluid line 36 on the outlet side of the actuating valve 39.

In the just-described color change cycle, it has been as sumed that thetwo paint control valves 28, 29 were being utilized to service a systemsupplying paint of a larger number of colors. In such cases, it isappropriate to supply solvent to the paint control valves, upstream ofthe paint inlets to the valves, in addition to supplying solvent to thepurge valve 27, in order to cleanse the valves themselves of previouslyused paint. However, in installations where a separate paint controlvalve is provided for each color, internal solvent cleansing of ajust-used paint valve would not be required, and it would not benecessary to provide the actuating valve 40 and its associated controlline 37. In a combined system, there may be a plurality of paint controlvalves continuously serving an equal number of.

regularly used paint colors, advantageously combined with a pair ofcontrol valves arranged in the manner of the valves 28, 29 of FIG. 1, tohandle a larger variety of relatively less frequently used colors. Wherea control valve is assigned permanently to a given paint color, thevalve itself need not, of course, be purged out during color change.Accordingly, the valve port Which otherwise would serve as a purgingsolvent inlet can be utilized as a paint outlet and connected to themain paint supply for the assigned color. This enables the paint to bekept in continuous circulation, even when not in use.

The system of the present invention represents an advantageouscombination of manual and automatic control facilities to provide aneffective and relatively sophisticated color change cycle, which iseconomical of time and supplies and yet which can be installed withoutundue cost and complication.

It should be understood that the specific system and components hereinillustrated and described are intended to be representative only, ascertain changes may be made therein Without departing from the clearteachings of the disclosure. Accordingly, reference should be made tothe following appended claims in determining the full scope of theinvention.

I claim:

1. A semi-automatic color change system for a paint spray installation,which comprises (a) a valve-controlled paint spray nozzle,

(b) supply and discharge fluid flow lines leading to and away from thevalve of said paint spray nozzle,

(c) a controllable discharge valve associated with said discharge line,

(d) a plurality of controllable paint valves associated with said supplyline,

(e) a controllable purge valve associated with said supply line upstreamof said paint valves,

(f) separate pressurized color paint supplies connected to said paintvalves for selective discharge into said supply line when one of saidvalves is open,

(g) separate pressurized solvent and air purge fluid supplies connectedto said purge valve for selective discharge into said supply line whensaid purge valve is open,

(h) purge control means operative when said purge valve is open tocontrollably block the flow of one of said purge fluids,

(i) a cycle timer control operative in timed sequence (1) open saiddischarge valve,

(2) open said purge valve,

(3) block off the purging solvent supply to accommodate air purging offirst-color paint through said supply and discharge lines and saiddischarge valve,

(4) thereafter block off the purging air supply to accommodate solventpurging of residual paint through said supply and discharge lines andsaid discharge valve,

(5) during the solvent purging step, open the paint nozzle momentarilyto purge and clear the nozzle,

(6) reblock the purging solvent supply to accommodate air purging ofsolvent through said supply and discharge lines and said dischargevalve,

(7) open a second-color paint valve to flow second-color paint into saidsupply and discharge lines,

10 (8) during the second-color paint flow, open said paint nozzlemomentarily to purge said nozzle of residual solvent and prime it withsecondcolor paint, and (9) close said discharge valve,

(j) said plurality of paint valves being connected in series with saidpurge valve and said supply line, whereby said purge fluids flow by eachof the paint valves.

2. A semi-automatic color change system for a paint spray installation,which comprises (a) a paint spray nozzle,

(b) independent fluid supply and discharge lines associated with saidnozzle,

(c) a controllable discharge valve in said discharge line,

(d) selectively controllable paint and purge fluid control valvesassociated with said supply line,

(e) said purge fluid valve being upstream of said paint valves, and

(f) a color change cycle timer associated with said valves and operativein sequence to' open said dis charge valve and direct into said supplyand discharge lines purge fluids and paint of a new color.

3. A color change sysem for a paint spray installation,

which comprises (a) a valved paint spray nozzle;

(b) a supply line connected to said nozzle for supplying paint andsolvent to said nozzle;

(c) a discharge line connected to said spray nozzle and communicatingwith said supply line only substantially at said spray nozzle;

(d) a plurality of controllable paint supply valves selectivelyconnectable to said supply line;

(e) a controllable solvent supply valve selectively connectable to saidsupply line and located upstream of said paint supply valves; and

(f) a controllable discharge valve in said discharge line.

4. The color change system of claim 3 further including (a) a reclaimreceptacle connected to said discharge line.

References Cited UNITED STATES PATENTS 2,022,481 11/1935 Schellenger239-127 X 2,196,176 4/1940 Brigham 137-15 2,290,350 7/1942 Olches239-124 X 2,430,697 11/1947 Allan 239-415 2,537,681 1/1951 Lawrence239-127 X 2,564,392 8/1951 Burrucker 239-415 2,616,654 1l/1952 Perkins251-143 2,659,389 ll/l953 Harvey 251-143 2,754,228 7/1956 Bede 239-1243,043,366 7/1962 Wentworth 239-415 3,058,668 10/1962 Harrnes et al. 239-3,134,508 5/1964 Bayer et al. 222-1445 3,139,238 6/1964 Norstrud et al.239-414 3,140,049 7/1964 Norstrud et al. 239-304 3,145,930 8/1964Herklotz et al. 239-304 X 3,146,950 9/1964 Lancaster 239-112 3,176,9224/1965 Decker 239-112 3,179,341 4/1965 Plos et al. 239-112 3,229,9111/1966 Carlson et al 239-112 M. HENSON WOOD, JR., Primary Examiner. R.S. STROBEL, VAN C. WILKS, Assistant Examiners.

2. A SEMI-AUTOMATIC COLOR CHANGE SYSTEM FOR A PAINT SPRAY INSTALLATION,WHICH COMPRISES (A) A PAINT SPRAY NOZZLE, (B) INDEPENDENT FLUID SUPPLYAND DISCHARGE LINES ASSOCIATED WITH SAID NOZZLE, (C) A CONTROLLABLEDISCHARGE VALVE IN SAID DISCHARGE LINE, (D) SELECTIVELY CONTROLLABLEPAINT AND PURGE FLUID CONTROL VALVES ASSOCIATED WITH SAID SUPPLY LINE,(E) SAID PURGE FLUID VALVE BEING UPSTREAM OF SAID PAINT VALVES, AND (F)A COLOR CHANGE CYCLE TIMER ASSOCIATED WITH SAID VALVES AND OPERATIVE INSEQUENCE TO OPEN SAID DISCHARGE VALVE AND DIRECT INTO SAID SUPPLY ANDDISCHARGE LINES PURGE FLUIDS AND PAINT OF A NEW COLOR.
 3. A COLOR CHANGESYSTEM FOR A PAINT SPRAY INSTALLATION, WHICH COMPRISES (A) A VALVEDPAINT SPRAY NOZZLE; (B) A SUPPLY LINE CONNECTED TO SAID NOZZLE FORSUPPLYING PAINT AND SOLVENT TO SAID NOZZLE; (C) A DISCHARGE LINECONNECTED TO SAID SPRAY NOZZLE AND COMMUNICATING WITH SAID SUPPLY LINEONLY SUBSTANTIALLY AT SAID SPRAY NOZZLE; (D) A PLURALITY OF CONTROLLABLEPAINT SUPPLY VALVES SELECTIVELY CONNECTABLE TO SAID SUPPLY LINE; (E) ACONTROLLABLE SOLVENT SUPPLY VALVE SELECTIVELY CONNECTABLE TO SAID SUPPLYLINE AND LOCATED UPSTREAM OF SAID PAINT SUPPLY VALVES; AND (F) ACONTROLLABLE DISCHARGE VALVE IN SAID DISCHARGE LINE.